16 replies to this topic

[Stian1979]

I have ben looking around for material to make my own cylinder liners and cast iron off G1 qualety seam to be the best, but also imposible to get my dirty hands on.

I gues I could use some old cast iron waterpipes, but it's all PVC nowdays.

Is there anny good replacement?
I could buy G1 cast iron pipes, but I don't want to buy so mutch. I just want enough to replace the liner in the famely motorbike, a new cylinder unit would only cost me 20USD, but I want to fix the old one just for funn.

I'm shure you all understend.

[cosworth bdg]

Your stuck between a rock and a hard place, unfortunately...............

[Stian1979]

Originally posted by cosworth bdg
Your stuck between a rock and a hard place, unfortunately...............

Could you atleast try to make me feel bether

[malbear]

Stian1979,
I assume that you have some workshop facility.
What bore size are you looking for?
old air cooled 1200 to 1500 VW engines are a good source of cast iron finned cylinders . you could turn off the finns and then bore it to size if the measurements will allow
Cheers malbeare

[Stian1979]

Originally posted by malbear
Stian1979,
I assume that you have some workshop facility.
What bore size are you looking for?
old air cooled 1200 to 1500 VW engines are a good source of cast iron finned cylinders . you could turn off the finns and then bore it to size if the measurements will allow
Cheers malbeare

Reanult 4 liners are also good, one off my friends used that for he's honda cb100(cb127 when he was done)
I'm looking for bore betwen 40-50mm

I gues the moust easy way would be to start casting myself

[J. Edlund]

You can also make the liners of steel, for example: http://www.matweb.co...assnum=NBUCOR05

[malbear]

Stian1979

nodular ductile cast iron is also good as it is not brittle . I have also used it to make piston rings as it does not have any gauling issues when sliding over the same material.

http://en.wikipedia....ki/Ductile_iron

[Powersteer]

What about finishing? Whats the recomended skin tone?

[Stian1979]

Originally posted by J. Edlund
You can also make the liners of steel,

I heard drag racers do liners out of steel because they can take more preshure, but the steel liners are no good for long running intervals. Drag racers are put apart after eatch race.

Originally posted by malbear
[B]Stian1979

nodular ductile cast iron is also good as it is not brittle . I have also used it to make piston rings as it does not have any gauling issues when sliding over the same material.

http://en.wikipedia....ki/Ductile_iron

That might be what I'm looking for. Anny qualety you recomend?

[J. Edlund]

Originally posted by Stian1979
I heard drag racers do liners out of steel because they can take more preshure, but the steel liners are no good for long running intervals. Drag racers are put apart after eatch race.

The above mentioned steel alloy is used for cylinder liners, both top fuel and other applications. Since it's a tool steel we're talking about wear shouldn't be an issue. The hardness is about 50% greater than for grey cast iron.

Steel liners are used in dragracing classes such as top fuel since they can handle much higher pressures without cracking. But even with lower pressures there is a possebility to use a thinner liner if steel is used.

[Stian1979]

Hardness is not everything. Cast iron seams to lubricate bether. I had something about it in school why cast iron is bether than steel as liners, but I don't remember. I think it was the carbon made it glide bether.

[malbear]

If you require the best solution using forged aluminium pistons then an aluminium liner or sleave should be used as it has a greater expansion rate than cast iron similar to that of the piston , this allows closer tolerances. The only trouble is that the liner has to be coated with a suitable bore material like chrome or a metal carbide mix ( electrosil ) and that is expensive.

[Engineguy]

Originally posted by malbear
If you require the best solution using forged aluminium pistons then an aluminium liner or sleave should be used as it has a greater expansion rate than cast iron similar to that of the piston , this allows closer tolerances. The only trouble is that the liner has to be coated with a suitable bore material like chrome or a metal carbide mix ( electrosil ) and that is expensive.

I've seen some manufacturer comments in the past year about thin iron/steel liners assuming an expansion rate near that of aluminum, if they have an expanded surface area (i.e. grooved) on their OD as a "key" to lock them to the aluminum as they are cast in place in the aluminum block casting. If you think about it, that's what a plated, or iron sprayed bore surface does. It would be interesting to see a study of this.

[J. Edlund]

Originally posted by Stian1979
Hardness is not everything. Cast iron seams to lubricate bether. I had something about it in school why cast iron is bether than steel as liners, but I don't remember. I think it was the carbon made it glide bether.

Hardness is one important factor. Another important factor is the surface finish of the bore, in general I would expect that the plateau type finish is prefered on racing- and high performance engines given it's better oil retention, even though this results in an increased oil consumption.

It's true that graphite in the flaky grey cast iron cylinder materials can work as a solid lubricant. However, engines requiring a long life can use phosphorus alloyed iron which has a much higher hardness. Due to difficult machining this material are often limited to liners. There are also other possebilites for increased life such as nitriding and surface hardening. Chrome plated steel liners have also been porposed for diesel engines.

There are also several coatings that can used to prevent scuffing and/or to reduce frictional losses. These can be applied onto the bore surface or the piston. Top Fuel engines for example use a teflon coated hard anodized piston with their steel liners, this reduce scuffing.

Ductile a.k.a.nodular iron, unlike grey iron isn't flaky, instead it's graphite has a spherical shape. This makes ductile iron much stronger and less brittle, but it also means that ductile iron is more difficult to cast and to machine. In addition to that it won't work as a solid lubricant, this increase scuffing and it's also the reason for the poor machinability.

Another material option for cylinder liners is compact graphite iron. This type of iron is stronger and stiffer than grey iron, it also have better fatigue strength and some flaky properties. The latter reduce scuffing and also makes it easier to machine.

[Stian1979]

I think G1 is still my preference(but I can not find it in the corect dimensions)

compact graphite iron sound like a good number two.

Ductile number thre.

Steel I think is out off the question since the original cylinder is cast iron and matching with something too diferent would probartly end in some kind of problem.

[J. Edlund]

Originally posted by Stian1979
I think G1 is still my preference(but I can not find it in the corect dimensions)

compact graphite iron sound like a good number two.

Ductile number thre.

Steel I think is out off the question since the original cylinder is cast iron and matching with something too diferent would probartly end in some kind of problem.

There shouldn't be any problem swithing to steel. Ductile iron is similar to steel anyway.

Compact graphite iron should work well, it surely is a better option than grey iron. Trouble is its limited availibility. Sintercast offers test pieces of CGI, but these cylinders have an internal diameter of 78 mm or larger.

[MRB]

Not sure if anyone is still needing advice on liner material or coatings but if so Laystall can provide technical assistance. They do steel, Cast and Ally liners with Chrome or Nikasil. Min wall in steel is 1 mm

www.laystall.co.uk